1. Field of the Invention
The present invention relates to an air conditioner, and more particularly, to a refrigerant bypassing and filtering apparatus of an air conditioner which filters a refrigerant circulated in the air conditioner to remove foreign matter from the refrigerant, and a method for controlling the refrigerant bypassing and filtering apparatus.
2. Discussion of the Related Art
Generally, air conditioning systems perform procedures of compressing, condensing, expanding and evaporating a refrigerant to cool and/or heat a confined space. Such air conditioning systems are classified into a cooling type wherein a refrigerant flows only in one direction through a refrigerant cycle, to supply cold air to a confined space, and a cooling and heating type wherein a refrigerant flows bi-directionally in a selective manner through a refrigerant cycle, to selectively supply cold air or hot air to a confined space.
Also, such air conditioning systems are classified into a general type wherein one indoor unit is connected to one outdoor unit, and a multi-unit type wherein a plurality of indoor units are connected to one outdoor unit. For the multi-unit type, an air conditioner may be implemented which includes at least one outdoor unit.
Multi-unit air conditioners are classified into a switching type wherein all indoor units operate in the same operating mode, that is, in cooling mode or heating mode alone, and a simultaneous type wherein a part of the indoor units operate in cooling mode, and the remaining indoor unit or indoor units operate in heating mode.
Meanwhile, such a multi-unit air conditioner is mainly used for an air conditioning system installed in a large-scale structure such as a building. In such a case, the refrigerant line connected between the outdoor unit and each indoor unit in the air conditioner must be lengthened. Such a lengthened refrigerant line is prepared by connecting pipes of a suitable length by means of welding or the like. In this case, however, slag formed on welded portions of the pipes may be separated from inner surfaces of the pipes, and circulated together with a refrigerant in the air conditioner during operation of the air conditioner.
When foreign matter such as the above-mentioned slag, which circulates together with the refrigerant, is accumulated on a certain portion of the refrigerant line, the refrigerant cannot flow smoothly. In particular, when the foreign matter is accumulated in a mechanical part of the air conditioner, for example, a compressor, abrasion and malfunction of mechanical elements may occur. In this case, the performance and reliability of the air conditioner are degraded.